Yes, you can definitely plant chilis/vegetables in plastic bags. In fact, planting in containers such as plastic bags can be a great option for those who don't have access to a garden or want to conserve space. Here are some steps you can follow to plant chilis/vegetables in plastic bags:

1. Choose the right bag: Select a large plastic bag that is sturdy enough to hold soil and can accommodate the roots of your plants. Make sure the bag has drainage holes to prevent waterlogging.

2. Fill the bag with soil: Fill the bag with potting soil or a mixture of garden soil and compost. Leave about 2-3 inches of space at the top.

3. Plant the chilis/vegetables: Make small holes in the soil and plant your chilis/vegetables. Be sure to space them out properly and follow the recommended planting depth.

4. Water regularly: Water the plants regularly, ensuring that the soil is moist but not waterlogged.

5. Provide nutrients: Fertilize the plants with a balanced fertilizer every few weeks to ensure they receive the necessary nutrients.

6. Provide support: Depending on the type of chili/vegetable, you may need to provide support for the plant as it grows. Use stakes or cages to support the plants.

7. Harvest: Once your chilis/vegetables are ready, harvest them regularly to encourage the plant to produce more.

Remember to choose a sunny spot for your plastic bag garden, and to monitor the moisture level of the soil regularly. With proper care, you can grow healthy and productive chilis/vegetables in plastic bags.